The subject matter disclosed herein relates to U.S. patent application Ser. Nos. 10/074,099 and 10/074,397, filed on Feb. 11, 2002, and U.S. patent application Ser. Nos. 10/325,048; 10/325,026; 10/324,999 and 10/324,983 filed on Dec. 20, 2002.
1. Field
The subject matter disclosed herein relates to data communication systems. In particular, embodiments disclosed herein relate to processing data received from an optical transmission medium.
2. Information
Optical communication networks have been implemented to enable increased data rates in links providing point to point communication. For example, optical communication links are typically implemented in Synchronous Optical Network/Synchronous Digital Hierarchy (SONET/SDH) and 10 Gigabit Ethernet systems. At a receiving end of such an optical communication link, a receiving module typically comprises a photodiode to generate a current in response an optical signal received from an optical transmission medium (e.g., fiber optical cabling). A transimpedance amplifier (TIA) typically converts the current generated by the photodiode into a voltage signal that is then processed. For example, the voltage signal may be processed by clock and data recovery circuitry to recover data transmitted in the optical signal. The photodiode and TIA are typically formed in distinct component where each component is provided with a distinct power supply.
A receiving module may also comprise a receive signal strength indicator (RSSI) to generate an RSSI signal representing the strength of an optical signal detected by a receiving photodiode. Such an RSSI signal is typically used for alignment of an optical fiber with respect to the photodiode to achieve optimal detection of the optical signal at the photodiode. Circuitry for generating an RSSI signal typically includes a circuit coupled directly to a photodiode independently of a TIA that may be used for processing signals from the photodiode. An RSSI signal is typically generated as a single-ended signal output signal having a voltage representing a strength of a detected optical signal where the voltage of the single-ended output signal is referenced to a common node of a circuit topology (e.g., a ground node).